If a person is allergic to penicillin he might show allergy to other related antibiotics like Cephalosporins.

If you are experiencing any rash, itching soles and feet, or generalised itching, hives, angio edema or swelling of lips, diarrhoea or abdominal cramps, nausea etc, please stop the antibiotic and consult your doctor to confirm the diagnosis and manage accordingly.